The present invention generally relates to allocating network resources. More specifically, the present invention relates to reserving and committing network resources based on an authorized quality of service.
The known signaling architecture H.323 is an International Telecommunications Union (ITU) defined standard that describes how multimedia communications occur between terminals, network equipment and services on local area networks (LANs) and wide area networks (WANs) that do not provide a guaranteed quality of service (such as Internet Protocol (IP) networks). Quality of service is a measure of communication service quality during a call, and can include, for example, the bandwidth, delay and latency associated with the call. In networks using connectionless xe2x80x9cbest effortxe2x80x9d delivery models, the quality of service typically is not guaranteed; the H.323 is a signaling architecture for such a network.
The H.323 provides a range of implementation options including gatekeeper-routed signaling. In the H.323 standard, gatekeepers map LAN address aliases to IP addresses and provide address lookups when needed. Gatekeepers also exercise call-control functions to limit the number of H.323 connections and the total bandwidth used by these connections in an H.323 xe2x80x9czone.xe2x80x9d Although the gatekeeper is not necessary within the H.323 standard, when a gatekeeper is present in a network, network terminals must make use of its services. In other words, gatekeepers maintain state information for each individual call and all call signaling must pass through the gatekeepers.
The gatekeeper implementation of the H.323 standard, however, suffers several shortcomings. First, the equipment associated with gatekeepers needs to be extremely reliable so that the gatekeeper is available throughout the course of the call. If the gatekeeper-related equipment fails during a call, the call fails because the state information for the call maintained solely at the gatekeeper is lost. Second, the gatekeeper-related equipment likely cannot scale in a cost effective manner because maintaining the state information and performing the messaging associated with H.323 is complex and processor intensive. Finally, theft of service is possible by bypassing the gatekeepers to place unauthorized and unmonitored calls.
Signaling messages are exchanged for a call between a calling party to a called party. A setup message for the call is exchanged through at least one gate controller. Network resources are reserved for the call based on the exchanged setup messages. An end-to-end message for the call is exchanged without the end-to-end message being routed through the at least one gate controller.
Call flows are aggregated into a single queue and a scheduling algorithm is used to partition bandwidth between the call flows and other classes of traffic. Per-flow signaling is only required near the edges of the network. This is achieved by introducing the abstraction of a pipe: a logical path, with a fixed bandwidth between non-contiguous xe2x80x9caggregationxe2x80x9d routers across the backbone. Admission control decisions for a call flow are made at the aggregation routers on either end of a pipe and do not require per-flow processing of signaling messages by the backbone routers. Backbone routers participate in the (coarser grained) signaling used to create a pipe or to re-provision the bandwidth associated with a pipe.